A kind of ternary catalyst for metal honeycomb carrier of motorcycle and preparation method
Technical field
The present invention relates to a kind of ternary catalyst for metal honeycomb carrier of motorcycle and preparation method.
Background technology
Motorcycle is the same with gasoline car, and the harmful components in the tail gas mainly are carbon monoxide, nitrogen oxide and hydrocarbon.Up to now, the most effective both at home and abroad at present improvement method is to adopt three-way catalyst to carry out external purification, it has made full use of the coordinative role of noble metal and complex rare-earth oxidate containing valuable metal, carbon monoxide, hydrocarbon, the oxidation of oxynitrides, reduction reaction in the tail gas be can promote, nontoxic carbon dioxide, water and nitrogen are translated into.Owing to simultaneously three kinds of harmful substances are converted into innocuous substance, so be called three-way catalyst.The common cellular material of carrier of carrying three-way catalyst, because its surface area is big, exhaust resistance is little.Consider factors such as carrier property, service condition, price, it is carrier that automobile generally adopts ceramic honey comb, and it is carrier that motorcycle then adopts metal beehive.To these existing many reports, and many patents of invention have been arranged both at home and abroad.
CN1915489 ternary Nano catalyst in use for cellular carrier of full metal and preparation method thereof and coating processes.This disclosure of the Invention a kind of ternary Nano catalyst in use for cellular carrier of full metal and preparation method thereof and coating processes, belong to the catalyst material field.The ternary nanocatalyst of this invention, the composition of lanthana (percentage by weight) 5~10wt%, cerium oxide 20~75wt%, zirconia 20~75wt%, the heat treatment specific area is greater than 30m
2/ g.The compound that employing contains zirconium, lanthanum, cerium ion is dissolved in deionized water, is configured to solution, dissolves in surfactant, and hydrothermal treatment consists is scattered in the organic solvent after washing, filter, and adds precious metal solution, continues to stir the back oven dry, calcination processing.Coating processes of the present invention is that the metal beehive carrier repeated ultrasonic is cleaned, and nanocatalyst is scattered in organic solvent, stir, and control solid content 5~40%, oven dry applies, calcining heat treatment.The present invention will handle at vehicle exhaust, and particularly the three-effect catalysis agent material of development of new low precious metal content, low light-off temperature has a good application prospect.
CN1413769 ternary catalyst for automobile tail gas exhaust gas treating device and preparation method thereof.This disclosure of the Invention a kind of ternary catalyst for automobile tail gas exhaust gas treating device and preparation method thereof that is used for, is first carrier with homemade cordierite honeycomb ceramic after mishmetal mine tailing, transition metal oxide modification, modified oxidized aluminized coating is second carrier, is active component with precious metals pt, Rh, Pd.Described modified aluminas is a double-decker, and interior modified aluminas is applied directly on the modification cordierite ceramic matrix, and on the modified oxidized aluminized coating, the noble metal active component then was carried on the modified oxidized aluminized coating in outer modified aluminas was coated on.The modifier of described modified aluminas is cheap mishmetal mine tailing, transition metal oxide and/or alkaline earth oxide.Use preparation method's provided by the invention catalyst, the ternary cleaner that cushioned layer and shell are made can be implemented purifying vehicle exhaust and handle.
CN101161337 three-way catalyst and preparation method thereof.This invention relates to a kind of purifying automobile tail gas that is used for, can be simultaneously to CO, HC, NO
xPlay three-way catalyst of catalytic purification effect and preparation method thereof.The ground floor Catalytic Layer is that activated alumina supports one or more the mixing in rare earth metal, the alkaline-earth metal, second layer Catalytic Layer is that aluminium oxide supports first active noble metals with mithridatism and non-zero residual activity, the 3rd layer of Catalytic Layer is second noble metal with catalytic activity, and the 4th layer of Catalytic Layer is the oxide of rare earth, alkaline earth or transition metal.This catalyst is made up of cordierite honeycomb ceramic matrix, alumina layer, active noble metals.The catalyst of this method preparation has catalytic performance and heat endurance preferably, and adapts to the air-fuel ratio scope of broad.
Three-way catalyst of the Mg-Al composite oxide of CN101249437 doping metals and preparation method thereof.This disclosure of the Invention a kind of three-way catalyst and preparation method thereof of the Mg-Al composite oxide that is used for the doping metals that vehicle exhaust handles, comprise honeycomb support and attached to the supported catalyst coating, the expression formula of described coating is Pd-Rh/MA or Pd-Rh/MA-M
N+, Pd-Rh is precious metal palladium and rhodium in the formula; MA is Mg-Al composite oxide (MgO-Al
2O
3); The metal of M for mixing, and M is the one pack system or the multicomponent of zirconium (Zr), cerium (Ce), barium (Ba), lanthanum (La), praseodymium (Pr) and neodymium (Nd); N+ is the charge number of doping metals; Wherein, the Mg-Al composite oxide of doping metals in the molar concentration rate of each metal be [Mg
2+]: [Al
3+]=1~1.5, n[M
N+]: ([Mg
2+]+[Al
3+])=0.1~0.2, when being multicomponent as if M, the molar concentration rate of doping metals is the inverse of the corresponding charge number ratio of metal; The ratio that the addition of precious metals pd and Rh accounts for the Mg-Al composite oxide quality of doping metals is respectively 0.1~0.5% and 0.01~0.05%.It is big that three-way catalyst exhaust gas treating device of the present invention has specific area, and high high-temp stability is good and the preparation method has simple.
The CN101479023 three-way catalyst has been described the two-layer three-way catalyst exhaust gas treating device that is used for purifying exhaust gas of internal combustion engine.This catalyst has excellent activity and temperature stability.Comprise activated alumina and first cerium/Zr mixed oxide in the ground floor of this catalyst on being coated to catalyst carrier, its two all carry out catalytic activation with palladium.With the second layer that waste gas directly contacts in, catalyst comprises activated alumina and second cerium/Zr mixed oxide equally, its two all carry out catalytic activation with rhodium.Second cerium/Zr mixed oxide has higher zirconia content than first mixed oxide.
China is world motorcycle production and consumption first big country, and annual production at present surpasses 2,000 ten thousand, accounts for the over half of whole world total output.The use of motorcycle has caused comparatively serious environmental pollution problem, and motorcycle exhaust is administered very urgent.The present invention adopts has that ignition is fast, volume is little, intensity is high, the metal beehive of good heat resistance is carrier, prepared a kind of ternary catalyst for metal honeycomb carrier that motorcycle exhaust is used that purifies, this catalyst has comprised two kinds of different active layers, make the removal effect of three kinds of pernicious gases such as hydrocarbon, nitrogen oxide and carbon monoxide all reach motorcycle state III discharge standard, and have price advantage.
Summary of the invention
The present invention seeks to: the preparation method that a kind of ternary catalyst for metal honeycomb carrier is provided, especially be applicable to that motorcycle uses, preparation contains the discrepant two kinds of catalyst of noble metal composition and the two series connection is used, to reduce the consumption of Noble Metal Rhodium, reduce processing cost, improved the clean-up effect of three kinds of pernicious gases such as hydrocarbon, nitrogen oxide and carbon monoxide in the motorcycle exhaust.Advantages such as this catalyst has also that ignition is fast, intensity is high, hear resistance and good mechanical property are particularly suitable for the tail gas clean-up of motorcycle.The honeycomb ceramic carrier that metal beehive is identical with hole density with volume is compared, and its specific area will exceed 0.4 times, thereby the more catalysis material of energy load, and clean-up effect is also more effective.
The object of the present invention is achieved like this: ternary catalyst for metal honeycomb carrier of motorcycle, form by metal beehive carrier, transition zone and active layer, earlier the stainless steel metal honeycomb substrate is cleaned and high temperature oxidation process, on the metal beehive carrier surface, form dense oxidation film; Load transition zone and active layer on metal beehive carrier then.The composition of transition zone is crystalline state γ-AL
2O
3Modified aluminas and land plaster; The composition of active layer is complex rare-earth oxidate containing valuable metal, auxiliary agent and minute amount of noble metal nitrate, makes two kinds of three-way catalysts of A, B according to noble metal component difference in the active layer; The detergent power that has improved carbon monoxide, hydrocarbon and nitrogen oxide is used in two kinds of three-way catalyst series connection.
The excessively preparation of layer slurry: one of transition zone composition is the γ-AL of crystalline state
2O
3, its preparation is to adopt gibbsite stone ([AlOOH] 3H
2O) react under 20 ℃~120 ℃ temperature with 50%~80% acetate is water-soluble, regulate pH<4, make the paste of solid content 40%~60%, its particle mean size is 1.2~1.5 μ m after tested.The another kind of raw material of filter course is commercially available land plaster.With the paste γ-AL that makes
2O
3(35~45%), land plaster (5~15%) add suitable quantity of water (40~60%) mixing, ball milling, and the ball milling time is that (drum's speed of rotation is 30~60r/min) to 50min~120min, promptly obtains the slurry of filter course.
The load of transition zone slurry: the transition zone slurry is full of the metal beehive carrier inner chamber, allows slurry fully contact also bonding with it, remove the inner chamber clout with the honeycomb substrate inwall.Then with load the metal beehive carrier of transition zone slurry 110 ± 15 ℃ of following heated-air dryings, and in the van-type electric furnace 500 ℃~600 ℃ following calcining 120 ± 30min, thereby make the metal beehive carrier that is loaded with transition zone, the load capacity of transition zone (dry weight) is 20~30g/L.
The active layer composition comprises complex rare-earth oxidate containing valuable metal (3CeO
2ZrO
20.1Y
2O
30.1La
2O
3), the auxiliary agent formed by nitrate such as two kinds of several or whole aluminium, magnesium, barium, nickel, manganese, strontium, cobalt, niobium, rhenium, copper, and the nitrate of minute amount of noble metal.Prepare two kinds of active layer slurries altogether, wherein the noble metal of A active layer slurries is platinum and palladium, and the relative weight of the two is 0.5~1 to 3~7, and complex rare-earth oxidate containing valuable metal is 7~9 to 1~3 with the relative weight of auxiliary agent; The noble metal of B active layer slurries is platinum, palladium and rhodium, and three's relative weight is 0.5~5 to 2.5~10 to 0.1~1.5, and complex rare-earth oxidate containing valuable metal is identical with the A active layer with the relative weight of auxiliary agent.A, B active layer material are mixed with water respectively, and regulating the pH value is 4.5~5.5, and (drum's speed of rotation is 44~46r/min) to ball milling 50min~120min, makes it to mix, and obtains the active layer slurry.
The load of active layer: the active layer slurry is full of the metal beehive carrier inner chamber, allows slurry fully contact also bonding with it, remove the inner chamber clout with the honeycomb substrate inwall.Then with load the metal beehive carrier of active layer slurries at 110 ± 15 ℃ of following heated-air drying 60min, and 350 ℃ of maintenance 30~60min allow nitrate decompose in the van-type electric furnace, again at 500~600 ℃ of following calcination 120min, thereby make ternary catalyst for metal honeycomb carrier.Two kinds of active layer slurries obtain A three-way catalyst and B three-way catalyst respectively.The load capacity of active layer (dry weight) is 80~100g/L, and the load capacity of noble metal (dry weight) is 1~3g/L.
Ce (NO with an amount of ratio (part by weight can be got the identical weight share)
3)
4, Zr (NO
3)
4, Y (NO
3)
3, La (NO
3)
3Aqueous solution, add the condensation reaction that is hydrolyzed of appropriate amount of PEG surfactant, form stable vitreosol.Through slowly polymerization between colloidal sol after the ageing, form the network structure gel.Gel makes 3CeO through 110 ℃ of dryings and at 600 ℃~720 ° following sintering 180~240min
2ZrO
20.1Y
2O
30.1La
2O
3
Purpose characteristics of the present invention are: 1. metal beehive carrier is carried out 800 ℃~1000 ℃ high temperature oxidation process, form the dense oxidation film with micropore.This helps improving load capacity and intensity of load on the one hand, then can prevent phenomenons such as the change of honeycomb scholar, distortion, honeycomb inner core that carrier at high temperature produces are released, honeycomb subsides on the other hand, improves the service life of metal beehive carrier under hot environment; 2. load adopts mechanical pneumatic actuation slurry to be full of the metal beehive carrier inner chamber, make it fully to contact and bond with it with inwall, again by the negative-pressure pipeline remaining slurry of carrier inner chamber of finding time, realize the load of slurries, advantages such as this method has that coating is evenly distributed, high conformity, intensity of load height, and the life-span is long.3. prepared and contained two kinds of different three-way catalysts of noble metal and series connection use, it is higher than the effect that a kind of catalyst is connected to the clearance of carbon monoxide, hydrocarbon, nitrogen oxide, both provides cost savings, and has also improved clean-up effect.
Description of drawings
Preparation technology's flow process of Fig. 1 ternary catalyst for metal honeycomb carrier
The specific embodiment
The technological process of ternary catalyst for metal honeycomb carrier mainly comprises as shown in Figure 1: metal beehive carrier preliminary treatment, transition zone preparation, transition zone mechanical load, drying and calcining, active layer preparation, active layer mechanical load, drying and steps such as calcining, product detection.
The metal beehive carrier preliminary treatment.At first selected suitable metal beehive carrier, its shell by the trade mark be 31OS, the material stainless steel that consists of 0Cr25Ni20 makes, inner core is that resistant to elevated temperatures Fe-Cr-Al alloy is made.The diameter of cylindrical metal honeycomb substrate is 25~63mm, 10~60mm, and hole density is 8~100 holes/cm
2, wall thickness 1~2mm, the hole be shaped as waveform, inner core and shell adopt soldering to fix.Then metal beehive carrier is carried out ultrasonic cleaning with distilled water and industrial degreasing agent, with the carbon distribution phenomenon that prevents that high temperature sintering from producing.Again carrier is carried out 800 ℃~1000 ℃ (being higher than the maximum temperature in the motorcycle exhaust pipe) high temperature oxidation process,, help the transition zone load to form dense oxidation film.High-temperature process also is phenomenon such as not release, honeycomb subsides for the change of honeycomb scholar, distortion, honeycomb inner core at high temperature do not take place carrier, improves the service life of carrier under hot environment.The high-temperature process effect be according to GB 11363-89 " soldering street corner Strength Testing Methods " to carrier being carried out static pressure test, to honeycomb shaft to applying 20Mpa/cm
2The honeycomb inner core should not snap, do not have release, non-loosening during pressure.
The transition zone slurry preparation step is as follows: the γ-AL that consists of crystalline state of transition zone
2O
3With commercially available land plaster, γ-AL
2O
3Preparation be to adopt gibbsite stone ([AlOOH] 3H
2O) react under 20 ℃~120 ℃ temperature with 50%~80% acetate is water-soluble, regulate pH<4, make the paste of solid content 40%~60%, its particle mean size is 1.2~1.5 μ m after tested.With the paste γ-AL that makes
2O
3(35~45%), land plaster (5~15%) add suitable quantity of water (40~60%) mixing, ball milling, and the ball milling time is that (drum's speed of rotation is 30~60r/min) to 50~120min, promptly obtains the slurry of filter course.
The load step of transition zone is as follows: get metal beehive carrier, transition zone slurry through ultrasonic cleaning ready, adopt mechanical pneumatic actuation to make the transition zone slurry be full of the metal beehive carrier inner chamber, allow slurry fully contact also bonding with it with the honeycomb substrate inwall, by the negative-pressure pipeline remaining slurry of carrier inner chamber of finding time, finish the load of transition zone again.Then with load the metal beehive carrier of transition zone at 110 ± 15 ℃ of following heated-air drying 60min, and in the van-type electric furnace 500 ℃~600 ℃ following calcining heat treatment 120 ± 30min, thereby make the metal beehive carrier that contains transition zone, the load capacity of transition zone (dry weight) is 20~30g/L.
The active layer slurry preparation step is as follows: the active layer composition comprises complex rare-earth oxidate containing valuable metal (3CeO
2ZrO
20.1Y
2O
30.1La
2O
3), the auxiliary agent formed by nitrate such as several or whole aluminium, magnesium, barium, nickel, manganese, strontium, cobalt, Niobium, rhenium, copper, and the nitrate of minute amount of noble metal.
The complex rare-earth oxidate containing valuable metal preparation is the Ce (NO with an amount of ratio
3)
4, Zr (NO
3)
4, Y (NO
3)
3, La (NO
3)
3Aqueous solution, add the condensation reaction that is hydrolyzed of appropriate amount of PEG surfactant, form stable vitreosol.Through slowly polymerization between colloidal sol after the ageing, form the network structure gel.Gel obtains through 110 ℃ of dryings and at 600~720 ° of following sintering 180~240min.
Auxiliary agent and noble metal nitrate aqueous solution to configuration carry out the dechlorination processing, be about to adjuvant water solution several or that all form by aluminium, magnesium, barium, nickel, manganese, strontium, cobalt, niobium, rhenium, copper nitrate, and by trace platinum, palladium, rhodium noble metal nitrate aqueous solution, under 50~80 ℃, 0.3~1.2Mpa, with 2.0~6.0m
3The flow velocity of/h is removed the chlorion in the aqueous solution by anion-exchange resin column.
Prepare two kinds of active layer slurries altogether, wherein the noble metal of A active layer slurries is platinum and palladium, and the relative weight of the two is 0.5~1 to 3~7, and complex rare-earth oxidate containing valuable metal is 7~9 to 1~3 with the relative weight of auxiliary agent; The noble metal of B active layer slurries is platinum, palladium and rhodium, and three's relative weight is 0.5~5 to 2.5~10 to 0.1~1.5, and complex rare-earth oxidate containing valuable metal is identical with the A active layer with the relative weight of auxiliary agent.A, B active layer material are mixed with water respectively, and regulating the pH value is 4.5~5.5, and (drum's speed of rotation is 44~46r/min) to ball milling 50~120min, makes it to mix, and obtains the active layer slurry.
The load step of active layer is as follows: the metal beehive carrier of transition zone of having got load ready, contain the active layer slurry of complex rare-earth oxidate containing valuable metal, auxiliary agent and trace platinum, palladium, rhodium noble metal nitrate solution, adopt mechanical pneumatic actuation active layer slurry to be full of the metal beehive carrier inner chamber, make slurry fully contact also bonding with it with the honeycomb substrate inwall, by the negative-pressure pipeline remaining slurry of carrier inner chamber of finding time, finish the load of active layer again.Then with load the metal beehive carrier of active layer material at 110 ± 15 ℃ of following heated-air drying 60min, and 350 ℃ of maintenance 30~60min allow nitrate decompose in the van-type electric furnace, calcine heat treatment 120min down at 500~600 ℃ again, thereby make ternary catalyst for metal honeycomb carrier.Two kinds of active layer slurries obtain A three-way catalyst and B three-way catalyst respectively.The load capacity of active layer (dry weight) is 80~100g/L on the carrier, and the load capacity of noble metal (dry weight) is 1~3g/L.
Detect.According to GB14622-2002 " motor exhaust pollutant emission limit and measuring method ", two kinds of three-way catalysts of metal beehive carrier (A and B) of preparation are as stated above tested through CG125 motorcycle driving 12000km tail gas clean-up result of the test.
Utilize the inventive method to obtain exemplary embodiments: a kind of ternary catalyst for metal honeycomb carrier that makes according to the method described above obtains the product (A and B) of two kinds of specifications.The volume of A resultant metal honeycomb substrate is φ
External diameter42mm * h50mm, hole density is 31 holes/cm
2, the noble metal in the catalyst activity layer is platinum and palladium, and the relative quantity of the two is 0.5~3 to 2.5~4, and the content of noble metal (dry weight) is 1~2.5g/L; Volume, the hole density of B resultant metal honeycomb substrate are identical with A, and the noble metal in the catalyst activity layer is platinum, palladium and rhodium, and the relative quantity of platinum, palladium, rhodium is 0.5~5 to 7~10 to 0.1~1.5, and bullion content (dry weight) is 1.5~2.8g/L.
Purify the tail gas clean-up technology path that adopts accurate adjustment carburetor+secondary air compensating+catalyst, its catalyst member is respectively with the series connection of 2 A three-way catalysts, 2 B three-way catalyst series connection or 1 A and 1 B series connection (A at preceding B in the back), and place in homemade certain CG125 vehicle blast pipe and carry out tail gas clean-up, table 1 is the clean-up effect of new car, and table 2 is the clean-up effects behind the 12000km of travelling.
Table 1 new car installs the three kinds of gas purging situations in catalyst front and back additional
Table 2 installs travel emission status behind the 12000km of new car behind the catalyst additional
Table 1 explanation new car uses 2 A three-way catalyst series connection, 2 B three-way catalyst series connection or 1 A and 1 B tandem energy to make the discharge value of carbon monoxide, hydrocarbon that decline significantly be arranged; 2 B three-way catalyst series connection or 1 A and 1 B tandem energy make the discharge value of nitrogen oxide that decline significantly be arranged; But the discharge value of 2 A three-way catalyst series connection the change basically nitrogen oxide.Table 2 explanation new car installs the catalyst three kinds of discharge of harmful gases values behind the 12000km of travelling additional, and its result and table 1 are similar.But three kinds of discharge of harmful gases values are higher than the numerical value before catalyst is installed in the table 1 after test is removed catalyst with car, and this is because due to test descends with the performance of the parts such as engine of car.Consolidated statement 1 and table 2, illustrate that Noble Metal Rhodium has the selection catalytic action to nitrogen oxide, consider that Noble Metal Rhodium is than platinum, palladium price height, therefore adopt 1 A three-way catalyst and 1 B three-way catalyst series connection to carry out catalysis, its clean-up effect can reach motorcycle and cross the III discharge standard, has price advantage again.The same length of above A and B three-way catalyst.